Wednesday, May 26, 2004
Rebuild front brake
Now I can work again I've replaced the seals in the front master cylinder and reassembled it after a thorough cleaning. Once the lever is removed the piston can be withdrawn from the cylinder. I was surprised how much slime there was in the bottom of the reservoir, together with rust on the steel parts. As the fluid is hygroscopic I shouldn't have been surprised.
The brake pipe was looking rough at each connector and I'd damaged one of them whilst undoing it. A new pipe was needed. The pipe has a rubber boot for the master cylinder and a piece of protective pipe on it, and these would need to be included on the new pipe. The companies I contacted weren't keen on me sending the old pipe as a pattern and then fitting my old bits so I decided to make the pipe up myself.
I'd been warned that this was unsafe and I can see that argument. However as I have stripped and rebuilt the master cylinder and I would be joining all the bits together, the pipe itself doesn't seem like the weakest link.
Assembly was straightforward but slow and fiddly. The hardest part was neatly splaying the braid to allow the olive to fit between it and the plastic pipe.
At the caliper end I've fitted a 120degree banjo instead of the OE male fitting. There were two reasons for this. Firstly I thought it would allow the pipe to fit more neatly without needing 2 bends. Secondly this means the pipe can be removed without removing the caliper.
I've reassembled the system, bled the air out and so far it hasn't leaked at any joint. It was a tough job getting the air out even though I had the caliper above the master cylinder.
Now I can work again I've replaced the seals in the front master cylinder and reassembled it after a thorough cleaning. Once the lever is removed the piston can be withdrawn from the cylinder. I was surprised how much slime there was in the bottom of the reservoir, together with rust on the steel parts. As the fluid is hygroscopic I shouldn't have been surprised.
The brake pipe was looking rough at each connector and I'd damaged one of them whilst undoing it. A new pipe was needed. The pipe has a rubber boot for the master cylinder and a piece of protective pipe on it, and these would need to be included on the new pipe. The companies I contacted weren't keen on me sending the old pipe as a pattern and then fitting my old bits so I decided to make the pipe up myself.
I'd been warned that this was unsafe and I can see that argument. However as I have stripped and rebuilt the master cylinder and I would be joining all the bits together, the pipe itself doesn't seem like the weakest link.
Assembly was straightforward but slow and fiddly. The hardest part was neatly splaying the braid to allow the olive to fit between it and the plastic pipe.
At the caliper end I've fitted a 120degree banjo instead of the OE male fitting. There were two reasons for this. Firstly I thought it would allow the pipe to fit more neatly without needing 2 bends. Secondly this means the pipe can be removed without removing the caliper.
I've reassembled the system, bled the air out and so far it hasn't leaked at any joint. It was a tough job getting the air out even though I had the caliper above the master cylinder.
| Rebuilding | Master cylinder seal kit Concertina for 'bullet' | Be careful not to scratch the cylider bore or the piston parts when stripping. Easy to refit with a spot of fresh brake fluid on them. |
| Brake pipe | 1050mm of braided hose 10x1.25 male connector 10x1.25 banjo bolt with 120 degree banjo connector with appropriate washers and olives |
Build with a lot of care! |
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